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Defining acute aortic syndrome after trauma: Are Abbreviated Injury Scale codes a useful surrogate descriptor?

Leach, R. BEng, BMedSci; McNally, Donal PhD; Bashir, Mohamad MRCS; Sastry, Priya MRCS; Cuerden, Richard BEng (Hons); Richens, David FRCS; Field, Mark FRCS, DPhil

Journal of Trauma and Acute Care Surgery: October 2012 - Volume 73 - Issue 4 - p 977–982
doi: 10.1097/TA.0b013e31825570d3
Original Articles

BACKGROUND: The severity and location of injuries resulting from vehicular collisions are normally recorded in Abbreviated Injury Scale (AIS) code; we propose a system to link AIS code to a description of acute aortic syndrome (AAS), thus allowing the hypothesis that aortic injury is progressive with collision kinematics to be tested.

METHODS: Standard AIS codes were matched with a clinical description of AAS. A total of 199 collisions that resulted in aortic injury were extracted from a national automotive collision database and the outcomes mapped onto AAS descriptions. The severity of aortic injury (AIS severity score) and stage of AAS progression were compared with collision kinematics and occupant demographics. Post hoc power analyses were used to estimate maximum effect size.

RESULTS: The general demographic distribution of the sample represented that of the UK population in regard to sex and age. No significant relationship was observed between estimated test speed, collision direction, occupant location or seat belt use and clinical progression of aortic injury (once initiated). Power analysis confirmed that a suitable sample size was used to observe a medium effect in most of the cases. Similarly, no association was observed between injury severity and collision kinematics.

CONCLUSION: There is sufficient information on AIS severity and location codes to map onto the clinical AAS spectrum. It was not possible, with this data set, to consider the influence of collision kinematics on aortic injury initiation. However, it was demonstrated that after initiation, further progression along the AAS pathway was not influenced by collision kinematics. This might be because the injury is not progressive, because the vehicle kinematics studied do not fully represent the kinematics of the occupants, or because an unknown factor, such as stage of cardiac cycle, dominates.

LEVEL OF EVIDENCE: Epidemiologic/prognostic study, level IV.

Supplemental digital content is available in the article.

From the University of Nottingham (R.L., D.M.); and The Trent Cardiac Centre (D.R.), Nottingham University Hospital, Nottingham; Thoracic Aortic Aneurysm Service (M.F.), Institute of Cardiovasular Medicine and Science, Liverpool Heart and Chest Hospital (M.B., P.S.), Liverpool; Transport Research Laboratory (R.C.), Berkshire, United Kingdom.

Submitted: April 28, 2011, Revised: March 6, 2012, Accepted: March 6, 2012. Published online: August 20, 2012.

This study was presented at the European Society for Cardiovascular and Endovascular Surgery Turkey 2010 and New York Aortic Symposium 2010 (appointed Editor’s Choice).

Supplemental digital content is available for this article. Direct URL citations appear in the printed text, and links to the digital files are provided in the HTML text of this article on the journal’s Web site (www.jtrauma.com).

Address for reprints: Donal McNally, PhD, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom; email: donal.mcnally@nottingham.ac.uk.

© 2012 Lippincott Williams & Wilkins, Inc.